Given that battery energy density is far less than that of liquid fuels such as gasoline and diesel fuel, the cost and weight of battery packs needed to produce an acceptable range in an electric vehicle are prohibitive, Shah said.

"This makes electric vehicles and plug-in electric vehicles a great challenge in a mainstream vehicle," Shah said recently in a speech at a conference sponsored by Plastics News on lightweight and electric vehicles.

Plastics News, like Automotive News, is published by Crain Communications.

Toyota has sold 3 million hybrids globally, Shah said. The Prius is by far the best-selling hybrid in the United States, with sales of 104,251 units this year through October – nearly half of the 211,598 total U.S. hybrid sales.

Aside from market leadership, Toyota uses the hybrid architecture as the basis for other alternative drivetrains such as plug-ins and EVs, he said: "Hybrid components can be easily adapted to other powertrain systems."

Shah said that Toyota sees a future for hydrogen fuel cell-powered vehicles, and plans to begin commercial sales in 2015. Its fuel cell vehicle has a range of nearly 500 miles per tankful and functions well in cold weather, he said.

Toyota sees fuel cell propulsion as optimum for large vehicles such as buses and delivery trucks, Shah said, particularly if they travel long-distance routes.